Noncoding RNA MIR22HG Research Articles

Review of the Different Outcomes Produced by Genetic Knock Out of the Long Non-coding microRNA-host-gene MIR22HG versus Pharmacologic Antagonism of its Intragenic microRNA product miR-22-3p.

Publications reveal different outcomes achieved by genetically knocking out a long non-coding microRNA-host-gene (lncMIRHG) versus the administration of pharma-cologic antagomirs specifically targeting the guide strand of such intragenic microRNA. This suggests that lncMIRHGs may perform diverse functions unrelated to their role as intragenic miRNA precursors. This review synthesizes in silico, in vitro, and in vivo findings from our lab and others to compare the effects of knocking out the long non-coding RNA MIR22HG, which hosts miR-22, versus administering pharmacological antagomirs targeting miR-22-3p. In silico analyses at the gene, pathway, and network levels reveal both distinct and overlapping targets of hsa-miR-22-3p and its host gene, MIR22HG. While pharmacological an-tagomirs targeting miR-22-3p consistently improve various metabolic parameters in cell culture and animal models across multiple studies, genetic knockout of MIR22HG yields inconsistent results among different research groups. Additionally, MIR22HG functions as a circulating endogenous RNA (ceRNA) or "sponge" that simultaneously modulates multiple miRNA-mRNA interactions by competing for binding to several miRNAs. From a therapeutic viewpoint, genetic inactivation of a lncMIRHG and pharmaco-logic antagonism of the guide strand of its related intragenic miRNA produce different results. This should be expected as lncMIRHGs play dual roles, both as lncRNA and as a source for primary miRNA transcripts.

Mir22hg facilitates ferritinophagy-mediated ferroptosis in sepsis by recruiting the m6A reader YTHDC1 and enhancing Angptl4 mRNA stability

BackgroundFerritinophagy-mediated ferroptosis plays a crucial role in fighting pathogen aggression. The long non-coding RNA Mir22hg is involved in the regulation of ferroptosis and aberrantly overexpression in lipopolysaccharide (LPS)-induced sepsis mice, but whether it regulates sepsis through ferritinophagy-mediated ferroptosis is unclear.MethodsMir22hg was screened by bioinformatics analysis. Ferroptosis was assessed by assaying malondialdehyde (MDA), reactive oxygen species (ROS), and Fe2+ levels, glutathione (GSH) activity, as well as ferroptosis-related proteins GPX4 and SLC3A2 by using matched kits and performing western blot. Ferritinophagy was assessed by Lyso tracker staining and FerroOrange staining, immunofluorescence analysis of Ferritin and LC-3, and western blot analysis of LC-3II/I, p62, FTH1, and NCOA4. The bind of YTH domain containing 1 (YTHDC1) to Mir22hg or angiopoietin-like-4 (Angptl4) was verified by RNA pull-down and/or immunoprecipitation (RIP) assays.ResultsMir22hg silencing lightened ferroptosis and ferritinophagy in LPS-induced MLE-12 cells and sepsis mouse models, as presented by the downregulated MDA, ROS, Fe2+, NCOA4, and SLC3A2 levels, upregulated GPX4, GSH, and FTH1 levels, along with a decrease in autophagy. Mir22hg could bind to the m6A reader YTHDC1 without affecting its expression. Mechanistically, Mir22hg enhanced Angptl4 mRNA stability through recruiting the m6A reader YTHDC1. Furthermore, Angptl4 overexpression partly overturned Mir22hg inhibition-mediated effects on ferroptosis and ferritinophagy in LPS-induced MLE-12 cells.ConclusionMir22hg contributed to in ferritinophagy-mediated ferroptosis in sepsis via recruiting the m6A reader YTHDC1 and strengthening Angptl4 mRNA stability, highlighting that Mir22hg may be a potential target for sepsis treatment based on ferroptosis.

Long non-coding RNA MIR22HG suppresses the chondrogenic differentiation of human adipose-derived stem cells by interacting with CTCF to upregulate CRLF1.

Improved chondrogenic differentiation of mesenchymal stem cells (MSCs) by genetic regulation is a potential method for regenerating articular cartilage. LncRNA MIR22HG has been proven to accelerate osteogenic differentiation, but the regulation mechanism of chondrogenic differentiation is still unclear. Human adipose-derived stem cells (hADSCs) have been widely utilised for bone tissue engineering applications. The present study aimed to examine the effect of MIR22HG on the chondrogenic differentiation of hADSCs. The results confirmed that MIR22HG was downregulated in the process of chondrogenic differentiation. Subsequently, gain- and loss-of-function of MIR22HG experiments showed that the overexpression of MIR22HG suppressed the deposition of cartilage matrix proteoglycans and decreased the expression of cartilage-related markers (e.g. Sox9, ACAN and Col2A1), whereas the knockdown of MIR22HG had the opposite effect. MIR22HG could bind to CTCF (CCCTC-binding factor), and CTCF could bind to the CRLF1 (cytokine receptor-like factor 1) promoter and upregulate CRLF1 gene expression. Besides, inhibition of CRLF1 can reverse the effect of MIR22HG on cell chondrogenic differentiation of hADSCs. Taken together, our outcomes reveal that MIR22HG suppressed chondrogenic differentiation by interaction with CTCF to stabilise CRLF1.

Long non-coding RNA MIR22HG inhibits the proliferation and migration, and promotes apoptosis by targeting microRNA-9-3p/ SOCS1 axis in small cell lung cancer cells.

This study aims to determine the role of long non-coding RNA (LncRNA) MIR22HG in small cell lung cancer (SCLC), and to explore its relevant mechanism. The expressions of genes and proteins in SCLC cells were examined applying qRT-PCR and western blot. Cell proliferation estimation was implemented utilizing cell counting kit-8 (CCK-8) and colony formation assays; the assessment of cell migration and invasion was operated employing Wound healing and Transwell; apoptosis evaluation was conducted adopting flow cytometric assay. Binding relationships was confirmed by luciferase reporter assay. Moreover, SCLC animal model was established to explore the role of MIR22HG in vivo. It was found that MIR22HG was declined and miR-9-3p was elevated in five SCLC cell lines (NCI-H446, NCI-H69, SHP-77, DMS79 and NCI-H345) in comparison with normal human bronchial epithelial cell line (NHBE). More interestingly, overexpression of MIR22HG resulted in decreased cell viability, declined colony formation, diminished capacities of cell migration and invasion in NCI-H446 and NCI-H345 cells but induced more apoptotic cells. However, these impacts were reversed by miR-9-3p upregulation. Meanwhile, MIR22HG could bind to miR-9-3p and negatively regulate its expression in SCLC. What's more, LncRNA MIR22HG overexpression was also testified to elevate SOCS1 via downregulating miR-9-3p expression. Furthermore, in vivo study further confirmed the role of MIR22HG/miR-9-3p in tumor regulation of SCLC. In conclusion, MIR22HG in SCLC was found to modulate miR-9-3p level and might act as a possible biomarker for SCLC treatment.

AP4 suppresses DNA damage, chromosomal instability and senescence via inducing MDC1/Mediator of DNA damage Checkpoint 1 and repressing MIR22HG/miR-22-3p

BackgroundAP4 (TFAP4) encodes a basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factor and is a direct target gene of the oncogenic transcription factor c-MYC. Here, we set out to determine the relevance of AP4 in human colorectal cancer (CRC) cells.MethodsA CRISPR/Cas9 approach was employed to generate AP4-deficient CRC cell lines with inducible expression of c-MYC. Colony formation, β-gal staining, immunofluorescence, comet and homologous recombination (HR) assays and RNA-Seq analysis were used to determine the effects of AP4 inactivation. qPCR and qChIP analyses was performed to validate differentially expressed AP4 targets. Expression data from CRC cohorts was subjected to bioinformatics analyses. Immunohistochemistry was used to evaluate AP4 targets in vivo. Ap4-deficient APCmin/+ mice were analyzed to determine conservation. Immunofluorescence, chromosome and micronuclei enumeration, MTT and colony formation assays were used to determine the effects of AP4 inactivation and target gene regulation on chromosomal instability (CIN) and drug sensitivity.ResultsInactivation of AP4 in CRC cell lines resulted in increased spontaneous and c-MYC-induced DNA damage, chromosomal instability (CIN) and cellular senescence. AP4-deficient cells displayed increased expression of the long non-coding RNA MIR22HG, which encodes miR-22-3p and was directly repressed by AP4. Furthermore, Mediator of DNA damage Checkpoint 1 (MDC1), a central component of the DNA damage response and a known target of miR-22-3p, displayed decreased expression in AP4-deficient cells. Accordingly, MDC1 was directly induced by AP4 and indirectly by AP4-mediated repression of miR-22-3p. Adenomas and organoids from Ap4-deficient APCmin/+ mice displayed conservation of these regulations. Inhibition of miR-22-3p or ectopic MDC1 expression reversed the increased senescence, DNA damage, CIN and defective HR observed in AP4-deficient CRC cells. AP4-deficiency also sensitized CRC cells to 5-FU treatment, whereas ectopic AP4 conferred resistance to 5-FU in a miR-22-3p and MDC1-dependent manner.ConclusionsIn summary, AP4, miR-22-3p and MDC1 form a conserved and coherent, regulatory feed-forward loop to promote DNA repair, which suppresses DNA damage, senescence and CIN, and contributes to 5-FU resistance. These findings explain how elevated AP4 expression contributes to development and chemo-resistance of colorectal cancer after c-MYC activation.Graphical abstract

Long non-coding RNA MIR22HG suppresses cell proliferation and promotes apoptosis in prostate cancer cells by sponging microRNA-9-3p

ABSTRACT The present study was designed to discuss long non-coding RNA (lncRNA) MIR22HG expression in prostate cancer and to address its effect on prostate cancer cells. MIR22HG and microRNA (miR)-9-3p expressions in prostate cancer cells were examined with the use of quantitative real-time PCR (qRT-PCR). Cell counting kit (CCK)-8, colony formation, and TUNEL were conducted to determine cell viability and apoptosis. Immunofluorescence was employed for the detection of Ki67 expression, and western blotting was applied for the examination of apoptosis-related proteins. The relationship of MIR22HG and miR-9-3p was verified employing luciferase reporter assay. Indeed, low MIR22HG expression was discovered in prostate cancer cells. Subsequently, in vitro loss-of-function studies revealed that MIR22HG overexpression suppressed cell proliferation but promoted cell apoptosis, accompanied with a reduction in Ki67 and Bcl-2 expressions, as well as an elevation in Bax and cleaved caspase 3 expressions. In addition, MIR22HG was identified as a sponge of miR-9-3p and the impacts of MIR22HG overexpression on cell proliferation and apoptosis were partly hindered by miR-9-3p overexpression. In summary, MIR22HG acts as an anticancer gene in prostate cancer via inhibiting cell proliferation and promoting apoptosis by sponging miR-9-3p. This article may provide a novel insight into the treatment of prostate cancer.

Pan-cancer analysis of the expression pattern of long non-coding RNA MIR22HG

To conduct a pan-cancer analysis of the expression of long non-coding RNA (lncRNA) MIR22HG and explore its association with clinical characteristics. We analyzed the expression of MIR22HG in different tumors and its association with clinical staging, lymph node metastasis, tumor mutation burden (TMB) and microsatellite instability (MSI) using R package based on the Cancer Genome Atlas (TCGA) datasets. The relationship between MIR22HG expression and infiltrating immune cells was analyzed using TIMER algorithm. The association of MIR22HG gene alteration frequency with the clinical outcomes was examined using cBioPortal online software. Data form Genomics of Drug Sensitivity in Cancer (GDSC) were used to analyze the relationship between MIR22HG and the sensitivity of chemotherapy drugs. We specifically analyzed MIR22HG expression in hepatocellular carcinoma (HCC) and its correlation with sorafenib treatment using GEO database and verified the results in 12 pairs of HCC specimens. Kaplan-Meier analysis was performed to analyze the correlation of MIR22HG with the outcomes of sorafenib treatment. We also tested the effects of MIR22HG overexpression and knockdown on IC50 of sorafenib in HCC cells. MIR22HG was downregulated in most tumors (P < 0.05), where its deletion mutations were frequent, and associated with a poor prognosis (P < 0.05). In many tumors, MIR22HG expression level was correlated with clinical stage, lymph node metastasis, TMB, MSI, immune cell infiltration, immune checkpoint-related genes, and sensitivity to common chemotherapeutic drugs (P < 0.05). Among the 6 common infiltrating immune cells in cancers, neutrophil infiltration had the strongest correlation with MIR22HG expression level, especially in breast cancer, rectal cancer and kidney renal papillary cell carcinoma (P < 0.05). MIR22HG was downregulated in HCC in association with HCC progression (P < 0.05). In HCC patients, a low MIR22HG expression was associated with a favorable outcome after sorafenib treatment (HR=2.94, P=0.075) and was capable of predicting the response to sorafenib treatment (AUC=0.8095). Compared with the negative control, MIR22HG overexpression obviously reduced sorafenib sensitivity (with IC50 of 7.731 vs 15.61) while MIR22HG knockdown increased sorafenib sensitivity of HCC cells (with IC50 of 7.986 vs 5.085). MIR22HG expression level is correlated with clinical stage, lymph node metastasis, TMB, MSI, immune cell infiltration, and chemosensitivity in most cancer, suggesting its potential as an immunotherapeutic target and also a prognostic biomarker for tumors.

Long non-coding RNA MIR22HG inhibits the adipogenesis of human bone marrow mesenchymal stem cells with the involvement of Wnt/β-catenin pathway

Osteoporosis is a frequently occurring bone remodeling disorder worldwide with one characteristic being decreasing bone mineral density and a predisposition to bone fracture, which diminishes patients’ quality of life. Several studies showed that imbalance between the osteogenesis and adipogenesis of bone marrow mesenchymal stem cells (BMSCs) took part in the development of osteoporosis. In previous study, we found MIR22HG regulated the osteogenesis of human BMSCs positively. In this study, we found that MIR22HG was decreased during the adipogenesis of human BMSCs and exerted negative effects on adipogenesis with the involvement of Wnt/β-catenin signaling pathway both in vitro and in vivo. Nitazoxanide could inhibit Wnt signaling and relieve MIR22HG’s suppression on adipogenesis. These findings indicated that MIR22HG had great potential in clinical application for osteoporosis treatment and prevention.

Long noncoding RNA MIR22HG promotes Leydig cell apoptosis by acting as a competing endogenous RNA for microRNA-125a-5p that targets N-Myc downstream-regulated gene 2 in late-onset hypogonadism

Leydig cells (LCs) apoptosis is responsible for the deficiency of serum testosterone in Late-onset hypogonadism (LOH), while its specific mechanism is still unknown. This study focuses on the role of long noncoding RNA (lncRNA) MIR22HG in LC apoptosis and aims to elaborate its regulatory mechanism. MIR22HG was up-regulated in the testicular tissues of mice with LOH and H2O2-treated TM3 cells (mouse Leydig cell line). Interference of MIR22HG ameliorated cell apoptosis and upregulated miR-125a-5p expression in H2O2-treated TM3 cells. Then, the interaction between MIR22HG and miR-125a-5p was confirmed with RIP and RNA pull-down assay. Further study showed that miR-125a-5p downregulated N-Myc downstream-regulated gene 2 (NDRG2) expression by targeting its 3′-UTR of mRNA. What's more, MIR22HG overexpression aggravated cell apoptosis and reduced testosterone production in TM3 cells via miR-125a-5p/NDRG2 pathway. MIR22HG knockdown elevated testosterone levels in LOH mice. In conclusion, MIR22HG up-regulated NDRG2 expression through targeting miR-125a-5p, thus promoting LC apoptosis in LOH.Leydig cell apoptosis is responsible for the deficiency in serum testosterone in late-onset hypogonadism. This study reveals that lncRNA MIR22HG upregulates NDRG2 expression by targeting miR-125a-5p, thus promoting Leydig cell apoptosis in late-onset hypogonadism.

Overexpression of Long Non-Coding RNA MIR22HG Represses Proliferation and Enhances Apoptosis via miR-629-5p/TET3 Axis in Osteosarcoma Cells.

In this study, we evaluated the mechanism of long non-coding RNA MIR22 host gene (LncRNA MIR22HG) in osteosarcoma cells. Forty-eight paired osteosarcoma and adjacent tissues samples were collected and the bioinformatic analyses were performed. Target genes and potential binding sites of MIR22HG, microRNA (miR)-629-5p and tet methylcytosine dioxygenase 3 (TET3) were predicted by Starbase and TargetScan V7.2 and confirmed by dual-luciferase reporter assay. Cell Counting Kit-8, colony formation and flow cytometry assays were utilized to determine the viability, proliferation and apoptosis of transfected osteosarcoma cells. Pearson's analysis was introduced for the correlation analysis between MIR22HG and miR-629-5p in osteosarcoma tissue. Relative expressions of MIR22HG, miR-629-5p and TET3 were measured by quantitative real-time polymerase chain reaction or Western blot. MiR-629-5p could competitively bind with and was negatively correlated with MIR22HG, the latter of which was evidenced by the high expression of miR-629-5p and low expression of MIR22HG in osteosarcoma tissues. Overexpressed MIR22HG repressed the viability and proliferation but enhanced apoptosis of osteosarcoma cells, which was reversed by miR-629-5p upregulation. TET3 was the target gene of miR-629-5p, and the promotive effects of upregulated miR-629-5p on the viability and proliferation as well as its repressive effect on apoptosis were abrogated via overexpressed TET3. To sum up, overexpressed MIR22HG inhibits the viability and proliferation of osteosarcoma cells, which was achieved via regulation of the miR-629-5p/TET3 axis.

Long non-coding RNA MIR22HG inhibits glioma progression by downregulating microRNA-9/CPEB3.

Glioma is one of the most common and aggressive malignant intracranial tumors worldwide. Recently, non-coding RNAs have been found to play critical roles in the development of glioma. However, the exact mechanisms have not been fully elucidated. In the present study, reverse transcription-quantitative PCR was used to determine the expression level of the long non-coding RNA MIR22HG and microRNA (miR)-9, while western blot analysis was used to detect the protein expression level of CPEB3. The potential binding sites were predicted using the StarBase v2.0 online tool and the hypothesis was verified using a luciferase reporter assay. A Cell Counting Kit-8 assay was used to assess cell viability, while wound healing and Matrigel assays were used to determine the migration and invasion ability of glioma cancer cells. The results showed that MIR22HG expression level was decreased but miR-9 expression level was elevated in glioma tissues and cell lines. Furthermore, MIR22HG was found to sponge miR-9, while CPEB3 was the direct target of miR-9 in the glioma cell line. Functionally, MIR22HG regulated the proliferation, invasion and migration of the glioma cell line by targeting miR-9. CPEB3 may be involved in the progression of the glioma cell line. Taken together, these findings confirmed that MIR22HG suppressed glioma development by inhibiting the miR-9/CPEB3 axis and provides a novel therapeutic strategy for glioma treatment.

Functional characterization of the long noncoding RNA MIR22HG as a tumour suppressor in cervical cancer by targeting IGF2BP2.

Cervical cancer is the most common malignant tumour in the female reproductive tract, ranking second in the global cause of female cancer and seriously endangering women's health. However, the underlying mechanisms leading to cervical cancer are unclear. Previous studies have reported the roles and general underlying mechanisms of the long noncoding RNA MIR22HG (MIR22HG) in multiple types of tumours. In this study, we describe the functional role of MIR22HG as a tumour suppressor lincRNA by regulating metastasis, growth and invasion by performing a series of in vivo and in vitro experiments. Our data suggested that MIR22HG dramatically promoted cervical cancer apoptosis and inhibited invasion by targeting IGF2BP2. The long noncoding RNA MIR22HG targets IGF2BP2 as a tumour suppressor in cervical cancer. Our findings will be helpful for developing potential therapeutics for cervical cancer.

Long non-coding RNA MIR22HG promotes osteogenic differentiation of bone marrow mesenchymal stem cells via PTEN/ AKT pathway

Osteoporosis is a prevalent metabolic bone disease characterized by low bone mineral density and degenerative disorders of bone tissues. Previous studies showed the abnormal osteogenic differentiation of endogenous bone marrow mesenchymal stem cells (BMSCs) contributes to the development of osteoporosis. However, the underlying mechanisms by which BMSCs undergo osteogenic differentiation remain largely unexplored. Recently, long non-coding RNAs have been discovered to play important roles in regulating BMSC osteogenesis. In this study, we first showed MIR22HG, which has been demonstrated to be involved in the progression of several cancer types, played an important role in regulating BMSC osteogenesis. We found the expression of MIR22HG was significantly decreased in mouse BMSCs from the osteoporotic mice and it was upregulated during the osteogenic differentiation of human BMSCs. Overexpression of MIR22HG in human BMSCs enhanced osteogenic differentiation, whereas MIR22HG knockdown inhibited osteogenic differentiation both in vitro and in vivo. Mechanistically, MIR22HG promoted osteogenic differentiation by downregulating phosphatase and tensin homolog (PTEN) and therefore activating AKT signaling. Moreover, we found MIR22HG overexpression promoted osteoclastogenesis of RAW264.7 cells, which indicated that MIR22HG played a significant role in bone metabolism and could be a therapeutic target for osteoporosis and other bone-related diseases.

Interfering with long non-coding RNA MIR22HG processing inhibits glioblastoma progression through suppression of Wnt/β-catenin signalling.

Long non-coding RNAs play critical roles in tumour progression. Through analysis of publicly available genomic datasets, we found that MIR22HG, the host gene of microRNAs miR-22-3p and miR-22-5p, is ranked among the most dysregulated long non-coding RNAs in glioblastoma. The main purpose of this work was to determine the impact of MIR22HG on glioblastoma growth and invasion and to elucidate its mechanistic function. The MIR22HG/miR-22 axis was highly expressed in glioblastoma as well as in glioma stem-like cells compared to normal neural stem cells. In glioblastoma, increased expression of MIR22HG is associated with poor prognosis. Through a number of functional studies, we show that MIR22HG silencing inhibits the Wnt/β-catenin signalling pathway through loss of miR-22-3p and -5p. This leads to attenuated cell proliferation, invasion and in vivo tumour growth. We further show that two genes, SFRP2 and PCDH15, are direct targets of miR-22-3p and -5p and inhibit Wnt signalling in glioblastoma. Finally, based on the 3D structure of the pre-miR-22, we identified a specific small-molecule inhibitor, AC1L6JTK, that inhibits the enzyme Dicer to block processing of pre-miR-22 into mature miR-22. AC1L6JTK treatment caused an inhibition of tumour growth in vivo. Our findings show that MIR22HG is a critical inducer of the Wnt/β-catenin signalling pathway, and that its targeting may represent a novel therapeutic strategy in glioblastoma patients.

Long noncoding RNA MIR22HG is down-regulated in prostate cancer.

Prostate cancer (PCa) is one of the most common cancer in males. Previous studies indicated that MIR22HG was a tumor suppressor in various cancers. However, the expression pattern and functional roles of MIR22HG in PCa remained to be further investigated. In this study, we for the first time showed MIR22HG was down-regulated in PCa. Furthermore, we observed the lower expression levels of MIR22HG were significantly related to higher Gleason score and T stage. Of note, we found that higher MIR22HG expression was associated with better disease-free survival and overall survival time in PCa. Moreover, we constructed a MIR22HG mediated co-expression network. Bioinformatics analysis showed MIR22HG was associated with regulating inflammatory response, regulation of transcription, cellular response to tumor necrosis factor, neutrophil chemotaxis, cell-cell signaling, and TNF signaling pathway. These results showed that MIR22HG could serve as a novel biomarker for prostate cancer.

Prolyl hydroxylase substrate adenylosuccinate lyase is an oncogenic driver in triple negative breast cancer

Protein hydroxylation affects protein stability, activity, and interactome, therefore contributing to various diseases including cancers. However, the transiency of the hydroxylation reaction hinders the identification of hydroxylase substrates. By developing an enzyme-substrate trapping strategy coupled with TAP-TAG or orthogonal GST- purification followed by mass spectrometry, we identify adenylosuccinate lyase (ADSL) as an EglN2 hydroxylase substrate in triple negative breast cancer (TNBC). ADSL expression is higher in TNBC than other breast cancer subtypes or normal breast tissues. ADSL knockout impairs TNBC cell proliferation and invasiveness in vitro and in vivo. An integrated transcriptomics and metabolomics analysis reveals that ADSL activates the oncogenic cMYC pathway by regulating cMYC protein level via a mechanism requiring ADSL proline 24 hydroxylation. Hydroxylation-proficient ADSL, by affecting adenosine levels, represses the expression of the long non-coding RNA MIR22HG, thus upregulating cMYC protein level. Our findings highlight the role of ADSL hydroxylation in controlling cMYC and TNBC tumorigenesis.

Long non-coding RNA MIR22HG inhibits cell proliferation and migration in cholangiocarcinoma by negatively regulating the Wnt/β-catenin signaling pathway.

Cholangiocarcinoma (CCA) is one of the most common primary biliary malignant tumors with a high mortality. MIR22HG has been reported to act as a tumor-suppressor gene in several types of cancers. However, the role and molecular regulatory mechanism of MIR22HG in CCA still remains unclear. The present study aimed to investigate the role and underlying mechanism of MIR22HG in CCA. The expression of MIR22HG was detected by RT-qPCR assayin CCA tissues and cells. CCK-8, colony formation and transwell assays were performed to study the biological function of MIR22HG in CCA. Western blot and immunofluorescence assays were performed to detect the expression ofWnt/β-catenin signaling pathway markers. In vivo assays were conducted to explore the biological role of MIR22HG. We first found that MIR22HG expression was significantly down-regulated in CCA tissues and cell lines. Moreover, MIR22HG expression was related to TNM stage and bore prognostic significance in CCA patients. Function experiments demonstrated that overexpression of MIR22HG inhibited cell proliferation, migration and invasion in CCA, whereas knockdown of MIR22HG caused the opposite result. It was found that MIR22HG negatively regulated mRNA and the expression levels of proteins in the Wnt/β-catenin signaling pathway (β-catenin, cyclin D1 and c-myc). The effect of MIR22HG overexpression on CCA progression could be partly rescued by activating the Wnt/β-catenin signaling pathway. MIR22HG suppressed CCA tumorigenesis in vivo. In summary, the results of the present study show that MIR22HG repressed cell proliferation, migration and invasion in CCA by negatively regulating the Wnt/β-catenin signaling pathway. MIR22HG may be a novel target for diagnosis and therapy in CCA.

Identification of Long Noncoding RNA MIR22HG as a Novel Biomarker in Thyroid Cancer.

Thyroid cancer (TC) is the one of the most common endocrine malignancy. However, currently there are no specific and sensitive biomarkers for predicting the prognosis for TC. In this study, we for the first time showed MIR22HG was down-regulated in thyroid cancer by analyzing public datasets, including TCGA, GSE29265, GSE33630, and GSE55091. Furthermore, we observed the lower expression levels of MIR22HG were significantly related to higher age, lymph node metastasis status, residual tumor status, N stage, Grade, and T stage in TC. We also observed higher MIR22HG expression was associated with longer overall and disease-free survival time in TC. In order to explore the potential mechanisms of MIR22HG regulating TC progression, 4 hub gene networks regulated by MIR22HG were constructed in the present study. Bioinformatics analysis showed MIR22HG was associated with apoptotic process, regulation of transcription, mRNA splicing, regulation of cell cycle, and Hippo signaling pathway in TC. These results suggested MIR22HG could serve as a novel biomarker for thyroid cancer.

Prognostic values of long non-coding RNA MIR22HG for patients with hepatocellular carcinoma after hepatectomy.

Hepatocellular carcinoma (HCC) is the fifth most frequently diagnosed cancer worldwide and the second most frequent cause of cancer death. The aim of this study is to identify the association between the expression of long non-coding RNA (lncRNA) MIR22HG and the clinical and tumor characteristics of patients with HCC, and to explore the prognostic significance of lncRNA MIR22HG on patients with HCC. We retrospectively reviewed 127 patients with HCC(42 female, 85 male) who were managed in our hospital between May 1st 2010 and June 30th 2016. The expressions of lncRNA MIR22HG were detected by real-time PCR. Prognostic factors were evaluated using Kaplan-Meier curves and Cox proportional hazards models. For the entire cohort of 127 patients, the normalized real-time PCR showed that the expression of lncRNA MIR22HG was lower in HCC tissues compared with corresponding nontumorous tissues. MTT assay showed that si-MIR22HG remarkably inhibited the proliferation tumor cells in three HCC cell lines including SMMC-7721, Huh-7 and Hep3B. Moreover, under-expression of MIR22HG was closely related to tumor encapsulation, microvascular invasion (MVI), and TNM stage. Cox proportional hazards analysis demonstrated that lncRNA MIR22HG under-expression was an independent risk factor associated with the prognosis of patients with HCC. In conclusion, we found that lncRNA MIR22HG expressed significantly lower in HCC tissues compared with non-tumorous tissues. Under-expression of lncRNAMIR22HG was an independent risk factor associated with the prognosis of patients with HCC.

748 Long Non-Coding RNA miR22HG Represses Hepatocellular Carcinoma Cell Invasion By Deriving miR-22 and Targeting HMGB1

748 Long Non-Coding RNA miR22HG Represses Hepatocellular Carcinoma Cell Invasion By Deriving miR-22 and Targeting HMGB1